1. Field of the Invention
The present invention relates to an ATM (Asynchronous Transfer Mode) network in the field of a network management operated by an operation company coupled to an information communication network, or a network management operated within a company. In particular, the present invention relates to an operation of the network management having a rerouting function in response to a fault of a structural component (a network element) provided on a PVC (Permanent Virtual Connection) route.
Further, the present invention relates to a method of managing a plurality of network elements in an ATM exchange network formed of a plurality of ATM exchanges, transfer units, routers, bridges, computers, etc. connected to each other through networks.
Still further, the present invention relates to a method of manually or automatically switching to another PVC route when a fault occurs at any one of network elements provided in the PVC route, as the operation from the network management system.
2. Description of the Related Art
There are common services to be improved, i.e., an improvement in the efficiency of an operator""s work in order to manage each domain of a network, and an improvement of service to an end user who utilizes the network. These common subjects should be solved in the network management system. Accordingly, the present invention aims to improve efficiency of the operation of the network management in the service field. On the other hand, an action to realize network standardization, for example, ITU-T Recommendation, ISO, etc., has been developed by network operation companies or by network equipment vendors.
For a fault of a line interface, it is possible to switch the faulty line interface to an alternate line interface based on an APS function provided in an ATM exchange. Conventional alternation systems provided in the ATM exchange have been disclosed, for example, in the Japanese Unexamined Patent Publication (Kokai) No. 8-242240, the Japanese Unexamined Patent Publication (Kokai) No. 5-160851 and the Japanese Unexamined Patent Publication (Kokai) No. 7-74747.
These documents, however, disclose an alternation system which can be utilized only for a faulty ATM exchange itself or only for a network element adjacent to the faulty ATM exchange. That is, the conventional alternation system cannot be applied to a PVC route from one end to the other end including the faulty ATM and network element.
In actuality, when the fault occurs in the ATM exchange so that it is necessary to provide a route which is alternate to the faulty ATM exchange, or when one of doubled VOD servers is faulty so that it is necessary to switch the faulty VOD server to the other VOD server, it is possible to solve the above switching process based on only operation from the network management system from the viewpoint of the whole of the network.
Further, as another conventional method, there is a method of searching another route just after the fault occurred, and determining an alternate route based on a result of search. However, a lot of time is required in this method so that it is very difficult to utilize this method in actual use.
Still further, when handling a very large network system, for example, an ATM network which is operated by a communication company, network elements themselves become very large and complicated, the amount of managing data and kinds which are held in each network element becomes large, and the number of network elements becomes also very large.
In the above case, in the network management system which handles managing data of network elements having such very large scale, many kinds and very large amount, when resolving a fault by using an alternation system when the fault occurs on the communication network, a lot of time is required for detecting the alternate route in real-time for each network element. Further, in the alternation function only for each network element, it is impossible to resolve the fault if the network element itself was broken down.
The primary object of the present invention is to provide a rerouting method which can quickly provide an alternate route when the fault occurs in an ATM network, in a network managing operation for each network.
Another object of the present invention is to provide a network management system which can quickly determine the alternate route and execute the rerouting process for the alternate route when the fault occurs on the PVC routes.
In accordance with one aspect of the present invention, there is provided a method of rerouting a PVC route on an ATM network, including steps of: previously defining an alternate route for the PVC route which is managed in an ATM network managing system; and switching the PVC route to a previously defined alternate route when a fault occurs in a network element forming the PVC route.
In a preferred embodiment, the method of rerouting the PVC route further includes step of determining an order of relief for a plurality of PVC routes in accordance with information of importance in which each PVC route previously holds when the fault occurs, and a step of rerouting the PVC route based on the order of relief.
In another preferred embodiment, the method of rerouting the PVC route further includes step of executing check of situation of the alternate route when the defined route cannot be used as the alternate route due to the fault or when a route is not defined as the alternate route, and step of notifying the situation.
In still another preferred embodiment, the method of rerouting the PVC route further includes step of notifying whether an alternation route should be returned to a previous route before alternation when the previous route is recovered during use of the defined alternate route, and step of returning to the previous route.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of, when defining the alternate route or at any time, comparing the alternate route with the previous route before alternation for each structural element of the PVC route on the alternate route defined when executing an actual switching process; sorting an element necessary for newly preparing in the alternate route after alternation with an element which can utilize the present element before alternation; and previously defining an effective switching order so as to omit a decision process when executing switching process.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of previously setting the alternate route for each segment, and re-setting the alternate route for only the segment which is disconnected, and making the alternate route which reroutes between only faulty segments on the PVC route which includes a plurality of segments.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of determining whether a present VP/VC on the alternate route can be utilized or not as the alternate route at registration of the same; executing registration as the alternate route for the VP/VC which was determined as the alternate route which can be utilized; and diverting an element VP/VC of another PVC route which exists on the alternate route.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of providing an interactive unit for a maintenance operator when executing alternate route switching process; providing a relief order information of a faulty PVC route, an attribute information of the faulty PVC route, and a candidate information of changeable PVC route to the maintenance operator; and determining the alternate route based on the maintenance operator""s decision.
In still another preferred embodiment, the method of rerouting the PVC route further includes step of, when there are a plurality of alternate routes, designating a priority order of change of the route in an alternate route list for each route, at registration by the maintenance operator or at any time, so that flexibility of route selection can be raised.
In still another preferred embodiment, the method of rerouting the PVC route further includes step of, when there are a plurality of alternate routes, extracting a degree of margin for an average value or a maximum value of a band in each structural element of the alternate route candidate from a resource managing function and an actual network when the fault occurs, so that an optimum changing order of the alternate route having a margin for the resource can be automatically set in the network managing system.
In still another preferred embodiment, the method of rerouting the PVC route further includes step of, when there are a plurality of alternate routes, assuming a line margin for line interface or connection in each structural element of the alternate route candidate when fault occurs, from transmission amount of cells or traffic information in the network managing system during a predetermined interval before the fault occurs; and comparing the information extracted from the network managing system and the actual network, so that a switching order of an optimum alternate route having little traffic can be automatically set.
In still another preferred embodiment, the method of rerouting the PVC route further includes step of, when there are a plurality of alternate routes, extracting an activity ratio of a CPU in the network element NE including each structural element of the alternate PVC route candidate when the fault occurs, from the network managing system and the actual network, so that an optimum alternate route switching order having little load on a CPU can be automatically set.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of previously setting a VP/VC for a PVC route on the alternate route, providing a situation in which the VP/VC for the PVC route to be alternated has been already completed on the alternate line when executing alternation, and switching only connections at a start point and end point of alternation when the line is disconnected.
In still another preferred embodiment, the method of rerouting the PVC route further includes steps of providing a unit for sharing the alternate route by a plurality of main routes, and providing a unit for notifying the shared situation and a used situation of the alternate route.
In accordance with another aspect of the present invention, there is provided a network management system connected to a plurality of network elements provided on a permanent virtual channel (PVC) route through a predetermined communication network, each network element includes an element data collecting unit and a fault notifying unit, and the system includes: an ATM network resource managing unit for managing resources included in the ATM network; a PVC connection managing unit connected to the element data collecting unit through the communication network for managing the situation of the connection of the PVC route; a PVC route searching unit for searching the PVC route; a faulty event analyzing unit for receiving a fault from the fault notifying unit through the communication network when the fault occurs at any one of network elements, and analyzing the fault; an alternate route defining unit for previously defining the alternate route for the PVC; and an alternate route processing unit for switching a faulty route to the alternate route defined by the alternate route defining unit when the fault occurs at any one of the network elements.
In a preferred embodiment, the alternate route defining unit includes an alternate route selecting unit and a faulty PVC route switching table; the alternate route selecting unit selects any one of PVC routes from the faulty PVC route switching table; and the faulty PVC route switching table is formed by a plurality of faulty element containing PVC routes and a plurality of changeable PVC routes each corresponding to each faulty element containing PVC route.
In another preferred embodiment, the network management system further includes a PVC relief order determining unit connected between the faulty event analyzing unit and the alternate route defining unit, for determining an order of relief for the PVC based on information of importance which is previously held in each PVC route, when the fault occurs, and the PVC connection managing unit includes connection information which are defined by an importance of a customer, an importance of continuity, a service class and a designation value by an operator, in order to select the alternate route.
In still another preferred embodiment, the network management system further includes an alternate route confirming unit connected between the alternate route defining unit and the alternate route processing unit, for checking and notifying the situation of another alternate route, when the defined alternate route cannot be used due to a fault, or when the alternate route has not yet been defined.
In accordance with still another aspect of the present invention, there is provided a network management system connected to a plurality of network elements provided on a permanent virtual channel (PVC) route through a predetermined communication network, each network element including an element data collecting means and a recovery notifying means, the system including: an ATM network resource managing unit for managing resources included in the ATM network; a PVC connection managing unit connected to the element data collecting unit through the communication network for managing situation of connection of the PVC; a PVC route searching unit for searching the PVC route; a recovery event analyzing unit for receiving recovery information from the recovery notifying unit through the communication network, when a fault is recovered at any one of network elements, and analyzing the recovery information from the recovery notifying unit; a previous route defining means for defining a route before alternation; and a recovery processing means for recovering the route.
In a preferred embodiment, the previous route defining unit includes a route selecting unit before alternation and a recovery PVC route switching table, the route selecting unit selects any one of PVC routes before alternation from the recovery PVC route switching table, and the recovery PVC route switching table is formed by a plurality of alternate PVC routes, a plurality of routes during alternation and a plurality of recovery element containing PVC routes.
In another preferred embodiment, the alternate route defining unit includes an alternate route establishing steps defining unit, an alternate route selecting unit, and a faulty PVC route switching table; the alternate route establishing steps defining unit includes, a PVC route overlap determining unit for determining overlap of the PVC route, an alternate route establishing steps analyzing unit, a data storage for storing route difference data, and an alternate route establishing steps data storage; and the faulty PVC route switching table includes a PVC list, an alternate route list and an alternate route preparing steps list.
In still another preferred embodiment, the faulty PVC route switching table is formed by the plurality of faulty element containing PVC routes having a PVC route collection list and a segment collection list in which one PVC route in the PVC route collection list corresponds to one segment collection list, and the changeable PVC route having an alternate route collection list in which one segment in the segment list corresponds to the alternate route collection list.
In still another preferred embodiment, the changeable PVC route further includes an alternate route PVC information list having a plurality of segments each having VP, VC and flag information, in which one PVC route in the alternate route collection list corresponds to the alternate route PVC information list.
In still another preferred embodiment, the network management system further includes a maintenance/interaction processing unit connected between the alternate route defining unit and a maintenance operator""s terminal.
In still another preferred embodiment, the alternate route defining unit further includes a maintenance/interaction switching unit.
In still another preferred embodiment, the alternate route defining unit includes an alternate route priority order defining unit having an alternate route manually defining unit connected a console which is handled by an operator, and an alternate route new priority order table; and a faulty PVC route switching table having the PVC list and the alternate route list in which one PVC in the PVC list corresponds to the alternate route list.
In still another preferred embodiment, the alternate route defining unit includes an alternate route priority order defining unit having a connection information analyzing unit connected to a console which is handled by an operator and further connected to the PVC connection managing unit, an alternate route automatically defining unit, and an alternate route new priority order table; and a faulty PVC route switching table having the PVC list and the alternate route list in which one PVC in the PVC list corresponds to the alternate route list.
In still another preferred embodiment, the network management system further includes an ATM network performance managing unit; the alternate route defining unit including an alternate route priority order defining unit having a traffic information analyzing unit connected to a console which is handled by an operator and further connected to the PVC connection managing unit and the ATM network performance managing unit, an alternate route automatically defining unit, and an alternate route new priority order table; and a faulty PVC route switching table having the PVC list and the alternate route list in which one PVC in the PVC list corresponds to the alternate route list.
In still another preferred embodiment, the alternate route defining unit includes an alternate route priority order defining unit having an activity ratio of a CPU analyzing unit connected to a console which is handled by an operator and further connected to the ATM network resource managing unit, an alternate route automatically defining unit, and an alternate route new priority order table; and a faulty PVC route switching table having the PVC list and the alternate route list in which one PVC in the PVC list corresponds to the alternate route list.
In still another preferred embodiment, the faulty route switching table includes a fault element containing PVC list, a segment list in which one PVC route in the faulty element containing PVC list corresponds to the segment list, an alternate route list in which one segment in the segment list corresponds to the alternate route list, and a segment list in which one alternate PVC route in the alternate route list corresponds to the segment list.
In accordance with still another aspect of the present invention, there is provided a network management system connected to a plurality of network elements provided on a permanent virtual channel (PVC) route through a predetermined communication network, each network element including an element data collecting means and a fault notifying unit, the system including: an ATM network resource managing unit for managing resources included in the ATM network; a PVC connection managing unit connected to the element data collecting unit through the communication network for managing situation of connection of the PVC; a PVC route searching unit for searching the PVC route; a faulty event analyzing unit for receiving a fault from the fault notifying unit through the communication network when the fault occurs at any one of network elements, and analyzing the fault; a sharing route defining unit for previously defining the sharing route for the PVC; a sharing route processing unit for determining the sharing route; and an alternate route processing unit for switching a faulty route to the alternate route defined by the sharing route processing unit when the fault occurs at any one of network elements.
In a preferred embodiment, the sharing route defining unit includes a sharing route selecting unit and a sharing PVC route table, the sharing route selecting unit selects any one of PVC routes from the sharing PVC route table, and the sharing PVC route table is formed by a plurality of faulty element containing PVC routes, a plurality of changeable PVC routes each corresponding to each faulty element containing PVC route, and a plurality of sharing or used situation each corresponding to each changeable PVC route.